A related-art air-conditioning apparatus having been proposed includes an internal heat exchanger that exchanges heat between refrigerant flowing from a condenser to an expansion device and the refrigerant flowing from an evaporator, thereby increasing the degree of subcooling of the refrigerant flowing from the condenser to improve the performance of a refrigeration cycle. Also, a related-art air-conditioning apparatus that can perform both a cooling operation and a heating operation having been proposed includes the above-described internal heat exchanger, thereby increasing the degree of subcooling of the refrigerant flowing from the condenser to improve the performance of the refrigeration cycle in both the cooling operation and the heating operation (see Patent Literatures 1 and 2).
In more detail, an air-conditioning apparatus described in Patent Literature 1 includes two internal heat exchangers on both sides of an expansion device to increase the degree of subcooling of refrigerant flowing from a condenser in both the cooling operation and the heating operation. That is, the air-conditioning apparatus described in Patent Literature 1 includes an internal heat exchanger between the expansion device and an outdoor heat exchanger that serves as the condenser in the cooling operation and an internal heat exchanger between the expansion device and the indoor heat exchanger that serves as the condenser in the heating operation.
An air-conditioning apparatus described in Patent Literature 2 includes two expansion devices on both sides of an internal heat exchanger to increase the degree of subcooling of refrigerant flowing from a condenser in both the cooling operation and the heating operation. That is, the air-conditioning apparatus described in Patent Literature 2 includes an expansion device that expands the refrigerant cooled by the internal heat exchanger in the cooling operation and an expansion device that expands the refrigerant cooled by the internal heat exchanger in the heating operation. Patent Literature 2 also discloses an air-conditioning apparatus in which a bridge circuit including four check valves is provided in a refrigeration cycle to increase the degree of subcooling of the refrigerant flowing from the condenser in both the cooling operation and the heating operation using a single internal heat exchanger and a single expansion device.